Relating to the motion of objects through space and time. Including concepts such as acceleration (thrust and gravity), mass, collision response, friction and more.

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2
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2answers
396 views

Collision detection via adjacent tiles - sprite too big

I have managed to create a collision detection system for my tile-based jump'n'run game (written in C++/SFML), where I check on each update what values the surrounding tiles of the player contain and ...
0
votes
1answer
3k views

Can someone explain Flappy Bird's physics to me? [closed]

I am having a difficult time trying to understand the Flappy Bird physics. I know it seems simple but I kind of suck at math. I am trying to see if I can make a simple game like this but it is just ...
0
votes
1answer
61 views

Proper Order to Process Each Frame

I'm writing a rudimentary 2D engine and am wondering what the proper or generally accepted order is for handling graphics, user input, sounds, and then other systems like physics. If you have written ...
1
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1answer
3k views

Moving rigidbody2d towards mouse click using AddForce

I cant get my rigidbody2d game object to move to where i click the mouse. The first click works. The object travels to the mouse click and stops. But the second time (or the third time) i click the ...
6
votes
3answers
458 views

How do you calculate the rotational velocity of a flying object?

When a arrow shaped object is fired it slowly adjusts it's rotation to match the direction it is moving. But what is the actual physics behind it? The question is: How many degrees does the ship ...
0
votes
1answer
284 views

Grid collision - finding the location of an entity in each box

I am trying to implement grid-based collision in a 2d game with moving circles. The canvas is 400x400 pixels. Below you can see the code for my Grid class. What I want it to do is check inside which ...
2
votes
4answers
2k views

Do two balls of different mass bounce different heights?

There are two balls and the only difference between them is the mass. Both are dropped from the same height on to the floor (static object with infinite mass), would both balls bounce up to the same ...
1
vote
1answer
349 views

Creating a vehicle using a physics engine [closed]

What is the theory behind creating a generic 3D vehicle in a physics engine? What I would like to know is what parts should I stick together to make the vehicle, how they parts should stick together, ...
-2
votes
2answers
925 views

How to calculate a bounding rectangle of a polygon?

Polygon poly = new Polygon(); poly.getPoints().setAll(5d, 15d, 15d, 25d, 5d, 30d); How do I calculate the Polygon's height and width? There is no poly.getWidth() or poly.getHeight() method in ...
0
votes
0answers
71 views

Lateral Friction Phisics

I am trying to create a physics engine for my game, and need to cancel out any lateral velocity for when entities turn. I have tried to mimic this page's example, but it is not working. I have objects ...
9
votes
3answers
869 views

Can I jump from A to B?

I'm making some rudimentary AI for my side-scroller and I need to know whether an AI unit can reach point B from point A simply by taking a jump. Flight trajectory of my characters is a bit unusal as ...
6
votes
1answer
737 views

How to do collision detection for fluids in 3D? [closed]

Is there an algorithm or a technique which can detect the collision between 3D fluids? I currently treat my fluids as dynamic meshes. Is it possible to find collisions with these, or will I need a ...
3
votes
1answer
2k views

Gerstner wave function simplified?

The gerstner wave function is a commonly used method to calculate waves and simulate water in video games and movies or most 3d simulations. It is however quite complex so it is very hard for young ...
2
votes
1answer
699 views

3d Water Simulation formula questions

I have created a Grid: At each point along the grid, is a vertex (Intersection Points): Each of these points has an x,y,z position. Vector3f(x,y,z). In an attempt to animate the grid into a group ...
2
votes
1answer
126 views

Where should the collision response/resolution code go?

I've got a collision response/resolution function that does the same for any pair of two entities. It's is in the World class right now. But right before that function is invoked, I have some ...
1
vote
0answers
44 views

Calculating Friction due to rotation from ball bounce? [duplicate]

In this question asked by codemonkey, The rotation will depend upon: upon impact, on: Initial Speed of the ball hitting the surface (magnitude of ball velocity vector) Friction co-efficient of ball ...
5
votes
2answers
1k views

How does this formula for generating water waves work?

I have been trying to implement the wave equation described in this paper ("Water Simulating in Computer Graphics," Kai Li and Liming Wu) in Java. Part of the paper discusses modeling waves as a sum ...
2
votes
0answers
54 views

How should I model rotation caused by bounce friction? [duplicate]

In my Java2D simulation, I have a disc which, when it bounces off the boundary of a 2D region, begins to rotate, as if it had gotten some spin from the wall. I'm having trouble relating the ...
8
votes
1answer
736 views

RK4, Derivatives, Understanding Game Physics

Gafferon Games has a great article on RK4 Integration for building physics simulations which can be found here: Integration Basics Personally my mathematics and physics knowledge could use ...
-2
votes
1answer
942 views

Simple collision detection implementation [closed]

I'm making a game with C++ where the program extracts the lines out of an image (via openCV), stores them in an std::vector< std::vector< int > > and the builds a tile map out of it which is ...
1
vote
2answers
2k views

Slope polygon collider 2D causing box collider 2D to 'bump' while sliding on it

I'm doing procedural terrain generation. So far I've created the mesh, and attached a 2D polygon collider to it. The terrain is made up of hills going up and down. After doing so, I put a 2D rigid ...
8
votes
3answers
348 views

How to take into consideration gravity when moving AI

I'm making a 2D game. There is currently a helicopter flying around, controlled by the player. It's controlled using the arrow keys: UP, LEFT and RIGHT. It's speed along the y axis is dy, and speed ...
0
votes
3answers
109 views

How to apply logarithmic type formula for speed?

I want my character's speed to ramp up using somewhat of a logarithmic formula. I am confused about how specifically I would implement this. I want the character to move fast with a little movement as ...
0
votes
3answers
1k views

Applying a torque to a different centre of mass

In Unity I have an object with a circle collider attached to it and when I apply a torque to this object's rigidbody2D, it rotates as expected. However, I have now attached a sub-object to this object ...
2
votes
1answer
619 views

Does client side prediction sync with the server in the past?

I've spent some time now messing around and just trying to learn dead reckoning and client side prediction for the fun of it. Most of what I do doesn't need it, so i've never had a need to go down ...
0
votes
1answer
3k views

How do I get parabolic movement in Unity using Rigidbody2d?

EDIT: It was the Animator after all. Apply Root Motion basically nullifies any physics based work. I "know" this answer but I can't figure out what can possibly be wrong. My code is in FixedUpdate(). ...
2
votes
3answers
862 views

How should I implement basic spaceship physics?

I am new to 2D game development. I've made several games, but they've made almost no use of physics. Now I want to try making a game that uses some basic physics to look more realistic. The game ...
0
votes
0answers
31 views

Steer a flock towards a target? Like in pikmin? [duplicate]

Can a flock be steered towards a target ? I've seen that flocking behavior has the alignement behavior, but can it be directed and steered toward a goal ? ...
1
vote
1answer
159 views

How do I calculate the motion of 2 massive bodies in space?

I'm writing code simulating the 2-dimensional motion of two massive bodies with gravitational fields. The bodies' masses are known and I have a gravitational force equation. I know from that force I ...
0
votes
1answer
48 views

What does it mean to cross a scalar with a vector in a 2D plane?

At the moment, I'm following this page to create a physics engine. As per that page, I need to cross angular velocity by a distance vector to get relative torque and such, but I'm not sure how (in a ...
1
vote
0answers
106 views

velocity of a ball after sliding down a inclined plane? [closed]

I am making kind of a game that involves inclined plane and physics simulation. In the Game a M kg ball at the constant speed of V is sliding up an inclined plane(inclined angle is θ) and the COF of ...
2
votes
2answers
797 views

Physics engine deltaTime and force acceleration

I am working on a physics engine that uses basic Euler integration to compute forces. So, here is the thing: function applyForce (rigidbody, force) { rigidbody.forces.add(force); } function ...
0
votes
2answers
689 views

Use both AddForceAtPoint and change velocity property?

I'm using Rigidbody2D for some game objects. It seems that when I AddForce() or AddForceAtPoint(), the game objects are mostly affected on the Y axis and hardly at all on the x axis. I don't ...
1
vote
2answers
168 views

How can I compute the movement of an object along a parabola?

I am working on a simple 2D game. In the game, I have a 'robot' that throws a ball towards another robot, in the shape of a parabola. Both 'robots' have the same Y coordinate. The program knows the ...
1
vote
1answer
2k views

OBB Collision Resolution: Jittering with Long Rectangles

I have been working on a physics simulation module. Almost everything works properly, but I am having an issue, which I have demonstrated in the following video. http://youtu.be/2L17y9Lme0Q As you ...
4
votes
1answer
272 views

How can I test if an object will “fit” during pathfinding?

I'm tinkering around with a 2d game where obstacles are polygons of arbitrary shapes, sizes and locations, and movable entities (players/enemies) can also be of arbitrary sizes. What's a good general ...
2
votes
1answer
4k views

Understanding Torque in Unity

This is (hopefully) a simple question that should avoid me asking a more complex question. This is in Unity (2D) but hopefully this is a general physics principle I am not getting. I am applying a ...
2
votes
2answers
254 views

How to obtain “gravity” and “initial impulse” given “desired time to reach max height” and “desired max height”?

I'm developing a 2d fighting game, using time steps based on frames ie, each call to Update() of the game represents a frame so, no variable time at all. My jump physics code doesn't need to consider ...
0
votes
1answer
236 views

Box2D + Citrus Engine - Proper Pong Paddles

I am creating a pong clone for my first Citrus Engine project using Box2D. I've tried two types of paddles, both do not fully work. 1) Paddle is a dynamic body with a restitution of 1.0 and friction ...
0
votes
3answers
495 views

How do I prevent other dynamic bodies from affecting the player's velocity with Box2D?

I'm working on my player object for my game. PhysicsBodyDef def; def.fixedRotation = true; def.density = 1.0f; def.position = Vec2(200.0f, 200.0f); def.isDynamic = true; def.size = ...
5
votes
2answers
763 views

Why are we not using integers in game physics?

We can use integer for game physics (or without physics, simply object representation): mass, position and rotation, where the integers represent, for example, the number of milligrams, millimeters or ...
-1
votes
1answer
3k views

No collision detected with 2D rigidbody

No collision detected with 2D rigidbody 0 I have a ZombieBoy with a circle collider2D and a box collider2D and a RigidBody2D . The player shots energy balls which has a Circle Collider2D and a ...
0
votes
2answers
11k views

Why would Rigidbody.AddForce not resulting in movement of my objects?

I'm trying to get my card objects to spread out randomly but nothing happens. I know the method is called cause I get the prints in the console for each card. But they don't move. No errors reported. ...
2
votes
1answer
399 views

Using Box2D / Physics with Tiles?

Here is my issue. I currently have Box2D setup and working. But, it works with my Entity system. So I can create static objects and dynamic moving ones, and they simulate fine. However, my world is ...
1
vote
2answers
586 views

How can I get the force of a collision in Love2D?

Is it possible to get the force of a collision between two objects in Love2D/Box2D? If so, how?
2
votes
3answers
821 views

Calculating 2D Physics Prediction of Shot Angle with Moving Velocity of both targets

I currently have the math right to hit a moving target with 99% accuracy as long as I don't move. When I start moving the aim is nearly 80%, it should also be 99% accuracy because the target is moving ...
3
votes
1answer
666 views

Car physics - velocity and latheral force

Im developing simple car racing game. To turn a car, I need to calculate slip angles for each tire and then use those angles to find lateral force (using Hans B. Pacejka magic formula). One thing I ...
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vote
2answers
75 views

Controls: Rolling on a ceiling

Currently I'm writing an iOS game where the basic movement is rolling. Technically you make the player turn clockwise or counterclockwise. When you tilt the device to the right, you will rotate ...
1
vote
1answer
239 views

AABB vs Rectangle

I'm trying to wrap my head around 2D physics and stumbled upon Axis Aligned Bounding Boxes, and I have a couple of questions regarding them. In all AABB structs I could find out there, people prefer ...
3
votes
2answers
103 views

Radiometric quantities and time in rendering

Often in papers people use various radiometric quantities, mostly radiant flux, radiant intensity, radiance and irradiance. It seems to me that all of these quantities are dependent on time. For ...